Mechanically tuned klystrons



Dec. 23, 1958 J. E. MccANN MECHANICALLY TUNED xLysTRoNs /NVENTOR JOHN E. Mc CAN/v TORNEV Nm @m M@ Mm Filed Deo. 2. 1953 um l\ Dec. 23, 1958 J. E. MocANN MECHANICALLY TUNED xLYsTRoNs 2 Sheets-Sheet 2 Filed Deo. 2. 1955` MECHANICALLY TUNED KLYSTRONS John E. McCann, Palo Alto, Calif., assignor to Raytheon Manufacturing Company, Waltham, Mass., a corporation of Delaware Application December 2, 1953, Serial No. 395,780

4 Claims. (Cl. 315-522) This invention relates to velocity modulation of di- Iected electron ow, and particularly to microwave oscillation generating systems employing electron discharge devices of the klystron type.

The invention resides in providing a klystron tube differing from prior tubes in the manner in which its beam control components may be assembled, and in the manner of tuning to the correct frequency factor for the service to which it is applied. 1

The successful operation of a klystron tube, as is well known, requires maintenance of precise dimensional relationships in the R. F. gap and resonant cavity controlling the energy output to an adjacent wave guide component of the associated system. As it is extremely diicult, with ordinary manufacturing methods, to achieve uniformity in the R. F. gap and resonant cavity dimensions, as between successively assembled tubes or groups of tubes, it is desirable to provide means for individually adjusting these dimensions as part of the integral structure of the device.

The present invention provides improved mechanical means for adjusting and maintaining the R; F. gap and resonant cavity dimensions of a klystron or equivalent velocity. modulating tube, so that temperature changes produce no distortion or drift; also, improvements in the structure, mode of operation, interrelationship, and a method of combining and assembling the various components affecting the efficiency and performance of a tube of this general classification.

The improvements herein disclosed include the provision of a balanced, pre-adjusted and securely locked assembly, symmetrical about the longitudinal axis of the tube, and operative to exert a constant gap and volume maintaining pressure along the transverse center line of a centrally located resonant cavity of regular contour and balanced proportions, the rectilinear rigidity of the control being brought about by reason of structural interrelationships affecting both the electron beam focusing and electron beam repelling components of the tube, which componentsare in turn in rectilinear alignment along said transverse center line.

' The complementary structures for beam control, just referred to, are in turn controlled by superimposed means for manually setting the R. F. gap between the focusing and repelling elements of the beam circuit, and concurrently establishing the corresponding volumetric dimensions of the resonant cavity. In this connection, a feature of the arrangement is the combining of coarse and fine adjustment elements in such manner as to establish an interlocking relationship affording greater positiveness in the maintenance of the parts in their adjusted setting.

Other characteristics of the invention will present themselves upon reference to the following description of one embodiment thereof as illustrated in the accompanying drawingsgwherein:

vFig. l is an enlarged scale broken longitudinal sectional "view of a klystron tube embodying the invention;

Fig. 2 is an exterior view of the tube of Fig. 1, on a scale greatly reduced from that of Fig. 1;

Fig. 3 is a plan view of a partial assembly of certain components of the tube constituting a basic sub-assembly to which related sub-assemblies are successively attached;

Fig. 4 is in part a sectional and in part a side elevation view of the partial assembly of Fig. 3; and

Fig. 5 is a sectional view along line 5-5 of Fig. 4, with certain parts removed.

Referring first to Fig. l, the illustrated tube has an elec-A tron gun circuit including a pair of circuit elements 11 and 12 extending from the tips of pins 13 and 14, respectively, to points well within the evacuated compartment 16 of the tube, these circuit elements being supported on,

the transversely disposed metallic header 17 through theV agency of the metallic eyelets 18 and 19, adapted to have sealed therein the pear-shaped glass beads 21 and 22, re-` spectively, secured to the circuit elements at the appropri ate locations to effect such mounting. Similar beads 23. and 24 are axed to electrode extensions 26 and 27, re spectively, and are sealed correspondingly in metallic: eyelets 28 and 29 carried by'a circular hoopor ring 32',l tting snugly within and adapted to be united, mechanically or thermally, to the inner cylindrical surface of the mainl metallic housing section 33 of the tube. The beam focusing and beam reflecting assemblies are disposed in alignment transversely of housing section 33, with their common axis passing through the center of a resonant cavity 36 formed by punching a hole through the cen-l trally disposed U-shaped metallic frame or block 37 Whose left-hand end is supported rigidly upon transversely disposed ring 32, as by thermal union therewith, and whose right-hand (yoke) portion is united with the vertical sides of the tapered wave guide 38, the latter terminating in the usual choke joint 39 supported, as by collar 35, on a cupshaped element 4t) carrying the wave guide window 41 and constituting the end closure element of the tube.

The formation of cavity 36 is completed by the elements 42 and 43, the former being a flexible corrugated sheet disposed over the punched hole in the block 37, and the latter being an integrated extensie-n of the lower side of the wave guide 38, closing the hole along the plane of the lower surface of block 3'7, as viewed in Fig. l. Elements 42 and 43 are essential parts of the beam repelling and beam directing assemblies, respectively, now to be described.

The beam directing (electron gun) assembly is illustrated in Fig. l as including a supporting cylindrical bracket or collar 44 fastened by screws 4S (see Figs. 3 and 5) o-r equivalently secured at its upper edge surface to the under surface of frame 37 having a diametrically slotted base Sll to which are secured the tabs 60 at the outer ends of laminated bridging holders 46. These bridges 46 have additional tabs or flanges 47 soldered to the outer one of a pair of concentric sleeves or ferrules 48 and 49 constituting the cathode carrier and cathode' shield, respectively, and whose upper ends constitute the electron emitting cathode 51 and beam focusing ring 52, respectively. The cathode lead 26 is connected to the inner cathode sleeve 48 by way of the interposed terminal 53 and connector ring 54 surrounding the base plug 56. The electrical connection between 53 and S4, as shown, is constituted by shield 49, but it may be independent of the shield and insulated therefrom, if potential differences so require. The plug S6 of insulating material is apertured to permit sliding it over the leads 55 supplying heating current to helically coiled filament 57, it being understood that the heating coil is iirst inserted within the inner ferrule 4S, with its coil ends extending therefrom, and the base ring 54 carrying plug 56 is then slipped over the coil leads and secured to the ferrule 48 through the agency of peripheral connector tabs 58. An

inverted cup-shaped element 59 is suitably secured-tothe inner cylindrical surface of mounting collar 44 and serves as a supporting member for the cavity floor 43 previously described. Element'59 has a depressed-and perforated central area 61 serving as an accelerator grid for the electron stream emitted from elementSl, and operates to bring the electrons to focus, inbeam form, below the R. F. gap constituted by frusto-conical grid r62 and fiat grid 63, formed integrally with cavity floor 43 and cavity ceiling 42, respectively, the upper grid`63 being an integrated-part of the beamrepelling assembly, now to be described.

The beam repelling, or beam refiectingassernbly is illustrated in Fig. l as including a pair of nested cylindrical elements. 66 and 67 laterally apertured to permit insertion of a lead 68'connecting the external line 12-27 withithe concave refiectorlelectrode- 69, the-latter` carrying -a nonconducting mounting'ring 70 to facilitate itssuspension upon a circular ledge formed on the lower cylinder v71, the element 66 being in turn supported upon the upper end surface of said lower cylinder 71. This 'mounting insures that reflector 69 will be axially aligned with` the R.-F. gap elements 62 and 63. The transversely aligned upper annular edge surfaces of parts 66 and67 arev united by soldering, or equivalent treatment, and serve-Jas a junction area 100 forattachment of thenovel gap-setting, or tuning, assembly now to be described.

The tuning assembly of the present invention is' shown as including a system of inter-engaged levers 73 and 74 constructed and combined in such a way as to make it possible to control the dimensio-n of the R. F.y gap with extreme precision, the motion reduction capacityof the tuning 'linkage'being'such that a fractional-turn lof the manually operable fine adjustment knob 76 produces a gap increment or decrement of micro-inch proportions, so that accurate tuning to any frequency along the tubes operating range may be accomplished quickly and smoo-thly. lTo accelerate the tuning procedure, thereisalsoprovided a coarse adjustment screw 78, whose lower'end presses upon the head 79 of a screw 80 threaded-'into a pair of aligned nuts81 and 82 disposed on opposite sides'of aflexible metallic diaphragm 83 sealing they opening in the depressed housing section 34 through-which the tuning assembly operates. lScrew 78 is provided with a knurled lock-nut 77, and exerts pressure along the'axis of the beam refiector assembly by reason of the reaction of its'threads upon a correspondingly threaded hole provided in the lever 74, the lever 74 being resiliently held against deflection about its pivot-bearing pin 72 during such operation by the resisting thrust exerted upwardly thereon at its outer toe 75, due to the upward bias of a leaf spring 84 whose outer end engages said lever and whose inner end is riveted to a rigid plate 85 constituting part of the rectangular box-like housing 90 whose side Walls support the ends of the two parallel pivot-bearing pins 72 and 98 of the tuning assembly and secured to the main tube housing section 33 by screws 86 passing through mating flanges on housing elements 85 and 91, respectively.

A longer leaf spring 92 has its inner end riveted to plate 85, and its outer end biased into contact with the extreme end portion of the under surface of lever 73, approximately in line with the axis of a screw 93 forming part of the tine adjustment assembly constituted by the knob 76, the upper screw 94, the scale-carrying sleeve 95, and the lower screw 93. -Screw 93 moves downwardly to exert defiecting thrust upon lever 73 as it is rotated within the-correspondingly threaded sleeve 96 rigidly h'eld upon the cover element 97 of the tuner housing, the lever 73 being pivotally mounted at the opposite end of the housing on the bearing pin 98, and equipped with a vrivet 99 whose downwardly directed head bears upon the upper surface of shorter lever 74, at the toe portion IS of the latter, to exchange thrust reactions therewith. It will be `understood that lever 73 is slotted through most of: its length to permit the nestingof the shorter lever 74 within the parallel sides of the longer lever 73. A third leaf spring 101 is interposed between the screw head 79 and the spacer 81, and has its ends bearing upon the tube housing element 33 to yieldably oppose downward deflection of the tuner assembly, and to damp vibrational tendencies. Nut 82 preferably has a ange 102 of the same diameter as the tianged upper surface of the beam reflecting assembly heretofore described.

.In assembling thecomponents, the first stepis to secure the cavity defining block 37, the waveguide` assembly 38, 39, the cavity defining ceiling and fioor elements 42 and 43, and the mounting ring 32 in assembled relationship, the peripheral edge surface of frame 37 being brazed to diametrically opposed crimped sections of the ring 32 along the inner surface of the latter, as indicated at 35 in Fig. 5. Prior to such assembly, the metallic eyelets 28 and 29 are also brazed or soldered to the ring 32..

The parts'just described constitute whatv may be termed sub-assembly'No. l.

Sub-assemblynNo. 2 consists of the beam directing components, including mounting collar .44, holder 46,.con centric ferrules 148 andst9,y and the accelerator. grid-carrying element S9. Terminal connector 53 4also isa part of this vsub-assembly.

vSub-assembly No. 3 consists of the beam reflecting components, including the nested elements 66 and.V 67the terminal connector 68, and the repeller, electrode:.69.

Sub-assembly No. 4 consists of the tuning components carried within rectangular box 90,v and including ,the two nuts 81 and 82, the interposed diaphragm 83, and the liange.102 matching the flanged area 100 of sub-assembly No. 3.

.When'sub-assemblies' 2, 3, and 4 are completed, subassemblies Zand 3 are butt-welded or brazed tothe floorand yceiling elements 43 and 42 of the resonant cavity, and the partial assembly consisting of sub-assemblies 1, 2 and 3 is then telescopically inserted into housing element 33, by way of the left-hand end thereof, the inner-structure being moved inwardly until ring 32 makes contact with the shoulder formed on housing element 33 by the step of inwardly deecting the diaphragm receiving section 34 of said housing element. The said ring 32 is then brazed, or otherwise secured to the housing, at the angularly centered position determined by causing dimple (Fig. 3) to register with housing depression 34. The final majorsub-assembling step'of inserting the 4tuner assembly may nowvbe performed. This finalmajor step involves bringing sub-assembly No. 4 into position,:such that the mating-.liar surfacesi102 and 100 a-but and coincide, whereupon they are united by application` of solder, or an equivalent fusing .treatment, for vwhich purpose the soldering or other fusing tools are inserted through one of the open ends of the cylindricalfhousing element 33. The remaining steps are to secure diaphragm83 to the housing wall .34, base 91 to the' housing element 33, coverv97 to' boxl 90, knob assemblies 76 and 77, end cup 40 into registry with -positioning ring 102 on the inner surface of thev housing element 33, circuit elements 26 and 27, and associated parts, to the terminal connectors 53 andy 68, respectively, and-transverse` partition 17 and terminal cap 103 to the -fiange .y 104 of Yhousing element y33, the parts .'17 and 103 having peripheral edges matching those of said fiange 104. However, prior to applying the terminal cap 103, the compartment` 16 is exhausted of air, to the customary degree, by application of suitable exhausting tubulation tothe open end of metallic exhaust tube 106 whoseflange 107 is welded Vto the apertured centralV surface of partition, 17. Aftery suchevacuating operation, the open end 108of tube 106 is closed in a conventional manner. 'The cap 103 is thenapplied, and serves to protect the tube 106 against damage.

It willbe understood that in addition to theA terminal pins 13 and'14,.there are other pins mounted in the cap 103 tov serve as terminals for leads (not shown) connecting with the two ends 55 of the cathode heater filament. These filament leads may be supported upon header 17 and ring 32 by the use of eyelets disposed in angularly spaced relationship to eyelets 18, 19 (for header 17) and eyelets 28, 29 (for ring 32), and similar thereto in structure. These additional parts do not appear in Fig. 1, as they are outside the plane of section represented in Fig. l; moreover, such eyelet and pin supports conform to well-known techniques of the art, needing no specific illustration.

This invention is not limited to the particular details of construction, materials and processes described, as many equivalents will suggest themselves to those skilled in the art. It is, accordingly, desired that the appended claims be given a broad interpretation commensurate with the scope of the invention within the art.

What is claimed is:

1. In an electron discharge device, a cavity resonator assembly including a fixed portion and a movable portion, said cavity resonator assembly having an axis disposed substantially perpendicular to said fixed and movable portions, coarse adjusting means including an adjusting screw aligned with said axis of said assembly and directly engaging said movable portion of said assembly for effecting movement of said movable portion during rotation of said crew, and fine adjustment means including a first lever, a second lever embracing said screw, and means for controllably actuating said first lever, the position of said second lever being independent of rotation of said screw, said first lever bearing against said second lever and responsive to actuation of said first lever to impart longitudinally directed thrust to said screw.

2. In an electron discharge device, a cavity resonator assembly including a fixed portion and a movable portion, said cavity resonator assembly having an axis disposed substantially perpendicular to said fixed and movable portions, coarse adjusting means including an adjusting screw aligned with said axis of said assembly and directly engaging said movable portion of said assembly for effecting movement of said movable portion during rotation of said screw, fine adjustment means including a first lever, a second lever embracing said screw, and means for controllably actuating said first lever, the position of said second lever being independent of rotation of said screw, said first lever bearing against said second lever and responsive to actuation of said first lever to impart longitudinally directed thrust to said screw, and means contacting said first lever and said second lever for yieldably applying a given force to said screw.

3. In an electron discharge device, a cavity resonator including a fixed portion and a movable portion, said cavity resonator assembly having. an axis disposed substantially perpendicular to said fixed and movable por tions, first means for effecting coarse adjustment of said resonator, second means for effecting fine adjustment of said resonator, said first means comprising a first adjusting screw aligned with said axis of said resonator and directly engaging the movable portion of said resonator for effecting movement of said movable portion during rotation of said first screw, said second means for adjusting including said first screw, a first lever, a first spring bearing against said first lever for applying a continuous force against said first lever, a second adjusting screw laterally offset from said first screw bearing against said first lever, a second lever mechanically engaging said first lever to impart longitudinally directed thrust to said first screw in accordance with the motion imparted to said second screw, the position of said second lever being independent of rotation of said first screw, and a second spring bearing against said second lever for applying a continuous force against said second lever.

4. In an electron discharge device, a cavity resonator including a fixed portion and a movable portion, said cavity resonator assembly having an axis disposed substantially perpendicular to said fixed and movable portions, first means for effecting coarse adjustment of said resonator, second means for effecting fine adjustment of said resonator, said first means comprising a first adjusting screw aligned with said axis of said resonator and directly engaging the movable portion of said resonator for effecting movement of said movable portion during rotation of said first screw, said second means for adjusting including said first screw, a first lever, a first spring bearing against said first lever for applying a continuous force against said first lever, a second adjusting screw laterally offset from said first screw bearing against said first lever, a second lever mechanically engaging said first lever to impart longitudinally directed thrust to said first screw in accordance with the motion imparted to said second screw, the position of said second lever being independent of rotation of said first screw, a second spring bearing against said second lever for applying a continuous force against said second lever, and a third spring engaging said resonator for yieldably opposing movement o'f said resonator.

References Cited n the file of this patent UNITED STATES PATENTS 2,257,400 Ray Sept. 30, 1941 2,421,273 Lafierty May 27, 1947 2,477,616 Jaynes Aug. 2, 1949 2,494,693 Ekstrand Jan. 17, 1950 2,497,564 Sorg Feb. 14, 1950 2,508,141 Broadway et al. May 16, 1950 2,513,277 Best July 4, 1950 2,513,371 Shepherd July 4, 1950 2,576,702 Scott Nov. 27, 1951 2,686,890 Davis Aug. 17, 1954 2,698,923 Edson Jan. 4, 1955 

